Death penalty states could face long-term complications after the move by the only U.S. manufacturer of sodium thiopental. California may have to revise laws governing its three-injection protocol.

The sole U.S. maker of the anesthetic used in executions announced Friday it would stop manufacturing sodium thiopental to prevent its product from being used to put prisoners to death.

Discontinuance of the drug that has been in short supply nationwide for the past year portends long-term complications for death penalty states. Some, like California, might have to revise laws governing executions and those seeking supplies from foreign makers may be turned away by countries that condemn capital punishment.

In California, the legal guidance for carrying out executions was amended in August after three years of debate and deliberation. The state's new protocols specify use of sodium thiopental as the first drug in the three-injection sequence, and any substitution would require the state to again revise the protocols, said Elisabeth Semel, a UC Berkeley law professor and director of the law school's Death Penalty Clinic.

Legal challenges to lethal-injection procedures have kept executions on hold for five years in California, where 718 prisoners are on death row. Corrections officials' attempt to carry out the execution of murderer Albert Greenwood Brown in September was thwarted by the litigation, as well as by the expiration of the state's last few grams of sodium thiopental.

Hospira Inc., of Lake Forest, Ill., stopped making its brand of sodium thiopental, Pentothal, at a North Carolina plant early last year because of an unspecified raw material supply problem. When Hospira attempted to move production to a factory in Liscate, Italy, near Milan, Italian authorities demanded assurances that the drug wouldn't end up in the hands of executioners. Hospira spokesman Dan Rosenberg said company officers couldn't make that guarantee and decided instead to "exit the sodium thiopental market."

"We cannot take the risk that we will be held liable by the Italian authorities if the product is diverted for use in capital punishment," Rosenberg said.

Sodium thiopental is a powerful barbiturate that has "well-established medical benefits" for patients, the spokesman said, adding that Hospira has never condoned its use in executions.

As Pentothal supplies have run out, some of the 35 states that allow capital punishment have had to postpone executions or obtain supplies of the drug from abroad.

Both supporters and opponents of capital punishment predicted the drug discontinuance would place new legal hurdles to executions.

"Long-term, I expect that the states will follow the lead of Oklahoma and switch to another drug without a supply problem," said Kent Scheidegger, legal director of the Criminal Justice Legal Foundation, which is in favor of the death penalty.

"Short-term, this requires going through the cumbersome regulation process with comment-spamming by the anti-death-penalty crowd," he said, urging the California Department of Corrections and Rehabilitation, which carries out executions at San Quentin State Prison, to start the legal revision immediately "so as to have it completed before an actual supply problem delays and denies justice again."

Richard Dieter, director of the Death Penalty Information Center, a nonprofit organization opposed to capital punishment that tracks death sentences, said states with the death penalty will now have to turn to a different anesthetic or seek sodium thiopental from a foreign supplier, "both of which have pitfalls."

Oklahoma has already executed two men using the anesthetic pentobarbital, commonly used to euthanize animals. But many states' statutes and protocols specify what drugs are to be used, and switching requires a lengthy legal review and submission for public comment, Dieter noted.

Importing sodium thiopental has raised questions about how to verify its purity and effectiveness, and the FDA has declined to take responsibility for vetting the imports, said Dieter.

California corrections officials imported a large quantity of sodium thiopental — enough for about 90 executions — from a British distributor in November, before a public outcry in Britain led to a ban on export of the drug to the United States. All European states have renounced the death penalty and many have legal restrictions against knowingly facilitating executions elsewhere.

U.S. District Judge Jeremy Fogel has been reviewing California's new lethal injection procedures and is expected to rule soon on whether they comply with the Constitution's ban on cruel and unusual punishment.